intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 110 insertions, 0 deletions

diff --git a/library/cpp/regex/pire/pcre2pire.cpp b/library/cpp/regex/pire/pcre2pire.cpp
new file mode 100644
index 0000000000..f788beb85f
--- /dev/null
+++ b/library/cpp/regex/pire/pcre2pire.cpp
@@ -0,0 +1,110 @@
+#include "pcre2pire.h"
+#include <util/generic/vector.h>
+#include <util/generic/yexception.h>
+
+TString Pcre2Pire(const TString& src) {
+    TVector<char> result;
+    result.reserve(src.size() + 1);
+
+    enum EState {
+        S_SIMPLE,
+        S_SLASH,
+        S_BRACE,
+        S_EXPECT_Q,
+        S_QUESTION,
+        S_P,
+        S_COMMA,
+        S_IN,
+    };
+
+    EState state = S_SIMPLE;
+
+    for (ui32 i = 0; i < src.size(); ++i) {
+        const char c = src[i];
+
+        switch (state) {
+            case S_SIMPLE:
+                if (c == '\\') {
+                    state = S_SLASH;
+                } else if (c == '(') {
+                    state = S_BRACE;
+                } else if (c == '*' || c == '?') {
+                    state = S_EXPECT_Q;
+                    result.push_back(c);
+                } else {
+                    if (c == ')' && result.size() > 0 && result.back() == '(') {
+                        // eliminating "()"
+                        result.pop_back();
+                    } else {
+                        result.push_back(c);
+                    }
+                }
+                break;
+            case S_SLASH:
+                state = S_SIMPLE;
+                if (c == ':' || c == '=' || c == '#' || c == '&') {
+                    result.push_back(c);
+                } else {
+                    result.push_back('\\');
+                    --i;
+                }
+                break;
+            case S_BRACE:
+                if (c == '?') {
+                    state = S_QUESTION;
+                } else {
+                    state = S_COMMA;
+                    --i;
+                }
+                break;
+            case S_EXPECT_Q:
+                state = S_SIMPLE;
+                if (c != '?') {
+                    --i;
+                }
+                break;
+            case S_QUESTION:
+                if (c == 'P') {
+                    state = S_P;
+                } else if (c == ':' || c == '=') {
+                    state = S_COMMA;
+                } else {
+                    ythrow yexception() << "Pcre to pire convertaion failed: unexpected symbol '" << c << "' at posiotion " << i << "!";
+                }
+                break;
+            case S_P:
+                if (c == '<') {
+                    state = S_IN;
+                } else {
+                    ythrow yexception() << "Pcre to pire convertaion failed: unexpected symbol '" << c << "' at posiotion " << i << "!";
+                }
+                break;
+            case S_IN:
+                if (c == '>') {
+                    state = S_COMMA;
+                } else {
+                    // nothing to do
+                }
+                break;
+            case S_COMMA:
+                state = S_SIMPLE;
+                if (c == ')') {
+                    // nothing to do
+                } else {
+                    result.push_back('(');
+                    --i;
+                }
+                break;
+            default:
+                ythrow yexception() << "Pcre to pire convertaion failed: unexpected automata state!";
+        }
+    }
+
+    if (state != S_SIMPLE && state != S_EXPECT_Q) {
+        ythrow yexception() << "Pcre to pire convertaion failed: unexpected end of expression!";
+    }
+
+    result.push_back('\0');
+
+    return &result[0];
+}